Sciatic nerve
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2008-05-29T08:44:42Z
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{{Infobox Nerve |
Name = Sciatic nerve |
Latin = nervus ischiadicus |
GraySubject = 213 |
GrayPage = 960 |
Image = Gray1244.png |
Caption = Left gluteal region, showing surface markings for arteries and sciatic nerve. |
Image2 = |
Caption2 = |
Innervates = [[Lateral rotator group]] (except [[Piriformis muscle|Piriformis]] and [[Quadratus femoris muscle|Quadratus femoris]]), [[Posterior compartment of thigh]] |
BranchFrom = [[lumbar plexus]] and [[sacral plexus]]: L4-S3 |
BranchTo = [[tibial nerve]], [[common fibular nerve]] |
MeshName = |
MeshNumber = |
DorlandsPre = n_05 |
DorlandsSuf = 12566006 |
}}
The '''sciatic nerve''' (also known as the '''ischiatic nerve''') is a large [[nerve]] that starts in the lower back and runs through the buttock and down the [[lower limb]]. It is the longest and widest single nerve in the body.
The sciatic supplies nearly the whole of the skin of the leg, the muscles of the back of the thigh, and those of the leg and foot.
==Anatomical course==
The nerve enters the lower limb by exiting the [[pelvis]] through the [[greater sciatic foramen]], below the [[Piriformis]] muscle.
It descends midway in the [[greater trochanter]] of the [[femur]] and the [[tuberosity of the ischium]], and along the back of the thigh to about its lower third, where it divides into two large branches, the [[tibial nerve|tibial]] and [[common fibular nerve|common peroneal nerves]]. This division may take place at any point between the sacral plexus and the lower third of the thigh. When it occurs at the plexus, the common peroneal nerve usually pierces the [[Piriformis]] muscles.
In the upper part of its course, the nerve rests upon the posterior surface of the ischium, the [[nerve to the Quadratus femoris]], the [[Obturator internus]] and [[Gemelli]]; it is accompanied by the [[posterior femoral cutaneous nerve]] and the [[inferior gluteal artery]], and is covered by the [[Gluteus maximus]].
Lower down, it lies upon the [[Adductor magnus]], and is crossed obliquely by the long head of the [[Biceps femoris]].
==Branches==
The nerve gives off articular and muscular branches.
* The '''articular branches''' (''rami articulares'') arise from the upper part of the nerve and supply the [[hip-joint]], perforating the posterior part of its capsule; they are sometimes derived from the [[sacral plexus]].
* The '''muscular branches''' (''rami musculares'') are distributed to the following muscles of the lower limb: [[Biceps femoris]], [[Semitendinosus]], [[Semimembranosus]], and [[Adductor magnus]]. The nerve to the short head of the Biceps femoris comes from the common peroneal part of the sciatic, while the other muscular branches arise from the tibial portion, as may be seen in those cases where there is a high division of the sciatic nerve.
The muscular branch eventually gives off the [[tibial nerve]] and [[common peroneal nerve]], which innervates the muscles of the (lower) leg. The tibial nerve goes on to innervate all muscles of the foot except the extensor digitorum brevis (peroneal nerve).
==Pathology==
Pain caused by a compression or irritation of the sciatic nerve by a problem in the lower back is called [[sciatica]]. Common causes of sciatica include the following low back conditions: [[spinal disc herniation]], [[degenerative disc disease]], [[spinal stenosis]], and [[spondylolisthesis]].
==In religion==
In the Jewish religion, consumption of the sciatic nerve is forbidden, even from otherwise kosher and properly slaughtered animals. This traditionally traces back to the Biblical account of [[Jacob]] being wounded when wrestling with the [[angel]].<ref>[http://www.sichosinenglish.org/books/chassidic-dimension-5/08.htm#t103 Vayishlach Minutiae]</ref> The sciatic nerve is known in [[Hebrew]] as gid hanasheh. The process of removing the sciatic nerve (as well as certain large blood vessels and forbidden fats) from the surrounding meat is known as nikkur, or "deveining." Since this is a difficult and delicate process, cuts from an animal's hindquarters are generally not sold as kosher.<ref>[http://www.chabad.org/library/article_cdo/aid/561078/jewish/Why-cant-I-find-kosher-filet-mignon.htm Why can't I find kosher filet mignon? - Kosher Q&A<!-- Bot generated title -->]</ref>
==Additional images==
<gallery>
Image:Gray344.png|Structures surrounding right hip-joint.
Image:Gray828.png|Plan of sacral and pudendal plexuses.
Image:Gray832.png|Nerves of the right lower extremity Posterior view.
</gallery>
==References==
{{reflist}}
==See also==
*[[Sciatica]]
==External links==
* {{DukeOrtho|sciatic_nerve}}
* {{MedlinePlusImage|19503}}
* {{NormanAnatomy|pelvis}} ({{NormanAnatomyFig|pelvicnerves}})
* {{NormanAnatomy|glutealregion}} ({{NormanAnatomyFig|glutealner}})
{{Gray's}}
{{Lumbosacral plexus}}
[[Category:Pelvic limb anatomy]]
[[Category:Peripheral nervous system]]
[[bg:Ишиас]]
[[de:Nervus ischiadicus]]
[[es:Nervio ciático]]
[[fr:Nerf ischiatique]]
[[ja:坐骨神経]]
[[pt:Nervo ciático]]
[[sv:Ischiasnerven]]